Sour running 2.5

Hi.. Im a new member with a broke down 2.5.. looking for thoughts and help. This was my daughters car which I have taken ownership of sitting in my driveway.

For several months, whenever she would pump gas, it didnt want to start after. Also, if you left it running while fueling it would stall. To get it running again, you would hold pedal to the floor to get it to fire.

It would constantly throw misfire codes after each fillup and the mysterious 420 code.

She broke down with it with lack of engine power in heavy heavy rain. Idled fine, but wouldnt go over 20mph.

Since sitting in my driveway, it barely idles and once you try to give it some gas, it quits. Only codes it currently is throwing is misfire codes. Mainly cylinder 2&4.

I replaced maf sensor, plug wires, and coil. Plugs were done 10k ago. Fuel pump runs when you turn key on, however I havent done fuel pressure yet. Going to check that.

Anyone have any ideas? It has 1 new converter on it.. would the other converter if plugged create this issue? Do we think there is an issue with the fuel pump that has finally showed up to stay? It seems something is getting agrivated when fuel goes in the car.

Any help appreciated.

I would start to look at the fuel tank evaporation system and the valve for it.

 

 

If it don't work as it should and for example feed fuel into the manifold when you are filling up the engine you'd get problems.

 

 

At least it's a starting point that you can check - unplug the hoses from the tank for the evaporation and plug them towards the engine. You may get a check engine lamp for it, but it's an emissions check condition and not something that would impact the driveability.

I am having a similar issue with my 2007 2.5 Started about a month ago when it didn't just start as normal. On third try, it started, but has since been unreliable at starting, although it runs fine when it does start, full acceleration, idles for 15 min at a time with no issue. It seems like it might be gas supply related. When I do crank it and there is no starting, I do not detect any gas fumes at the exhaust pipes. Currently shows 5/8 of a tank with 4 gal of 91 added a few days ago. The typical routine is that it cranks with no firing for 2-6 times, then it cranks and fires but with a petering out after a few seconds, and finally it starts and continues to run as long as acceleration is done for the first 5-10 sec. It will restart immediately, but after an hour it is back to ground zero. Also seems to start eventually when in sun and interior temp above 80, but in evening or morning it does not start, at least I don't go beyond 8 attempts lest I drain battery and now have two problems. I pulled and reinstalled what seemed to be all relevant fuses and relays. This issue started just before i replaced all 4 plugs, first O2 sensor, and VVL oil pressure switch (code 0028). No codes and I periodically check and clear anyway. I hate intermittent stuff, especially when all seems fine when it is running. Is it possible that fuel is being returned to the left side and the hose, whatever, which connects the two sides is not putting gas on the right side? It did start quickly after I added the gas the other day.

 

 

I have the Haynes manual which covers this 4th gen up to the 2006 model year, and much seems to be the same with the 2007.

 

 

 

TIA

 

 

Bob

I did some research on this last night, but didn't post what I came across since I wasn't sure how helpful it'd be.

 

Long story short, I'd be looking at the charcoal canister in one of the rear wheel wells, I forget which one it's in. OR it sounds like it could be a problem with this little purge valve that is either located on the front, or back of the intake manifold. I looked up prices last night, the little valve has a msrp of around $80 from Subaru, or $50 and $55 on rockauto, depending on which brand you get.

 

Here's a quote from another thread on a similar issue.

 

I'm going to take a wild ass guess here. Someone jump in an correct me if I'm wrong.

 

The purge system on the fuel tank works to suck vapor off the top of the tank to reduce the chance of it leaking out into the atmosphere harming the polar bears. It does this by using engine vacuum (via the intake manifold) to pull it through a charcoal canister and all the vapor then goes into the engine (albeit not much) to be burned. If the tank was over filled, a purge valve failed open, and has filled your charcoal canister with fuel, it may be pushing gas into the intake vacuum line causing a rich condition after the first start when filling.

 

I think your best bet is to start going through this purge system component by component to figure out where your bad part is. I've done this before, but not for YEARS. It sucks and requires the use of a hand vac pump to diagnose.

 

https://legacygt.com/forums/showthread.php/dies-after-stopping-gas-station-178472.html

 

Then there's the quote below, from the thread below.

"Quote:

Originally Posted by munkis

Sounds like you have a partially stuck open Canister Purge Valve (the one bolted to the intake manifold)

 

Its allowing vapor from the from the tank to enter the intake manifold during fueling this is causing the hard starting. All the vapors should be going into the canister."

https://forums.nasioc.com/forums/showthread.php?t=1828629&page=2

Thanks for reply and pointers. I finally located the Cannister Purge Valve which is now on the front of intake manifold, and not under, as a youtube vid showed. Pulled it off and could not blow through it and checked the resistance at 25 ohms. My thoughts are that it is OK, but got started a little late so will attack the vapor cannister in the AM as car parked on street at moment.

 

 

I am going to review the youtube vids again. This is starting to make me hate polar bears. ;-)

 

 

 

 

 

I went to gas station and got 3 gal of gas, I think about 9-10 gal in tank at moment and added it, as car did start after adding 4 gal of gas on Thursday.

 

I tried to start and got two sequences of 2 seconds of petering out, and then just cranking. I did detect some gas smell at the exhaust when I checked this time. Not sure how the computer reacts to a rich mixture. All hoses to intake manifold box looked good.

Next step is to just see what happens to the idle when you take off the gas cap.

The issue is not starting at all at the moment. I would dream of having an idle problem. Maybe I'll try starting it w/o gas cap on.

I ordered a fuel pump. Will be in today.. when I took fuel lines off to pull it, there was barely any pressure on the lines. Also, sock was completely plugged. Ill let you know it issue is resolved.

My issue turned out to be a wonky fuel pump relay. We got the pump to cycle for a few seconds on one of the key turns to "on." really nice of subie to include the really loud chime noise as you are trying to listen for something else. I think disconnecting it will rise to the top of my todo list. I'm going to detail it now on "what did you do 4th generation thread, todays date, vol 8, about page 177 or so.

... really nice of subie to include the really loud chime noise as you are trying to listen for something else...

 

Just plug your seatbelt into the receiver before sitting down to test. That'll solve the chime. (if it's the same chime that used to vex me when listening for things)

Here is where I currently am at.

Fuel pump replaced but didnt cure the problem. Replaced pcv valve because that was gummed up. Im noticing alot of sludge buildup in all the vacuum lines and intake ports. Car doesnt want to start unless I unplug the two pcv vacuum lines from the front of the intake. Will start right up and quit seconds later. Car also quits once I touch the throttle.

Car wont run long enough to throw codes.. totally stumped...

Have you smoked tested the evap system and the intake system? Tested the purge valve?

I did not. Dont have a smoke tester. Was going to do a fuel pressure test and oil pressure test. The town mechanic told me he ran test on car and it had no oil pressure....however Ive never had a code or oil light come on. In my reading.. it seems to have symptoms of bad fuel pressure regulator but also seems to have symptoms of map sensor or egr valve fail.

You can plug the evap valve, that should do away with that problem for the moment.

 

 

The oil light should be on when you just turn on ignition without cranking and go off almost directly when you crank. That would be enough to indicate if it's OK for a start of the engine. If not then you may have suffered the dreaded oil pickup tube fail.

 

 

 

Essentially you can plug all "unnecessary" hoses going to the manifold and let things like PCV vent to air instead when doing tests.

 

 

I had a similar event once - and it was because I had forgotten to connect one hose (I think it was the PCV hose) so the engine didn't get the airflow detection after it had made the start. But that was on an EA82T engine (crap engine).

I just did a fuel pressure check. Im reading 40lbs coming from tank and only 15lbs on the return line. Is that normal?

And why on earth is there coolant going to the throttle body?? Never seen that before in all my life lol!

Return line is just a flow back to the tank so that's not really indicative of anything.

 

 

The 40psi pressure seems normal. At least not a serious deviation from normal.

And why on earth is there coolant going to the throttle body?? Never seen that before in all my life lol!

 

 

It's used to prevent icing in winter conditions, so don't worry about it. It was probably something discovered in certain climate zones and then they just made sure it wouldn't cause trouble - Subies are after all common in areas with winter conditions.

Ok. I will get a vacuum tester and check the pressure regulator and purge valve. Ive had every hose on and off this thing trying to het it to run. So far it runs best when pcv valve hoses are unhooked from intake , but it still only runs for 30 seconds before shutting off.

One more thing that can cause that behavior - the immobilizer when it fails to detect the chip in your key. Do you have another key to try with?

Which cat did you replace?

Ive tried both keys.

 

Which cat? No clue. The lousy mechanic in town supposedly did one. The front right looks re-welded but doesnt look new to me. It seems to me that once the car builds any heat at all, it shuts off.

Vacuum test showed 5-8lbs. Hooked to brake booster line on intake.

You could disconnect the exhaust right before the cats and remove them. It’s be loud, but if it runs, then you know it’s likely a clogged cat. Otherwise it sounds like it’s been in need of maintenance. If you have sludge in the vacuum lines you could start replacing them or making sure they are clear with compressed air or similar.

You could disconnect the exhaust right before the cats and remove them. It’s be loud, but if it runs, then you know it’s likely a clogged cat. Otherwise it sounds like it’s been in need of maintenance. If you have sludge in the vacuum lines you could start replacing them or making sure they are clear with compressed air or similar.

 

You dont think its off a tooth at that low vacuum #'s?